Purge Chamber

Date 09-14-2007 18:43 Edited 09-14-2007 19:05

Just thought I'd show a few pics of the purge chamber I built as a test rig to prove out a welding process for a customer. The actual part will be welded in another much larger version of this that suits the part. It's for an aerospace application of welding 6/4 titanium. I have it set up with an automatic wire feed with a foot activated switch. I can purge the chamber down to 0.01% oxygen in about ten minutes without the use of vacuum. I also use compressed argon to run my pencil grinder encase of tungsten inclusions.
There is a copper tube all around the perimeter with 0.045" holes drilled every 1/2" to allow a good uniform purge of the chamber. The one way valve to purge the unit is built in below the perf plate that can be seen in the one shot. The wire feed unit seals as it is screwed into the chamber (old mig whip). The gloves are rubberized sandblast gloves. They are held on with a large industrial rubber band and then we tape them to ensure they cannot be pulled off during use. We use a oxygen sensor to determine the oxygen content prior to welding. This particular model will be good for our future application as it has a long stainless "snout" that can be pushed down into long tubes atc, to ensure all entrapped air has been removed from the drop thru side of the weld prior to welding.
We like it much better then the flexible bags, they are a real pain to work in, kind of like sticking your hands into a marshmellow and trying to weld.
I'll try to add the pics now.
Regards
Jim
P.s. I'll get some shots of test pieces as they come out in the as welded condition.

Attachment: Chamber1.jpg (371k)

Attachment: Chamber2.jpg (341k)

Attachment: Chamber3.jpg (335k)

Attachment: Chamber4.jpg (351k)

Attachment: Chamber5.jpg (350k)

Attachment: Chamber6.jpg (282k)

Attachment: Chamber7.jpg (389k)

Attachment: Chamber8.jpg (303k)

By aevald

Date 09-14-2007 19:28

Hello jd369, those are really nice shots and a nice looking chamber, appears as though it will work really well for your application and sounds as though you've covered your bases. Would enjoy seeing some of the finished product as well. Regards, aevald

By Tommyjoking (****)

Date 09-15-2007 07:32

That wire feed system is slick as greased owl sh*t...you ought to patent that one brother!!!!! Purge box is always the best wtg on TI ....you got a nice solution there. If you don't mind I might show this around at work a bit. What did you use for the feed motor? did you just scavenge off a mig or what? We don't do much TI anymore but I can dang sure think of of some ss applications this would save some time on.

By jd369

Date 09-16-2007 03:16

Hey Tommyjoking
I didn't build that wire feed, originally I did scavange one from an old Sciaky automated tig welder but it burnt out after a month of use (it was close to 40 years old though). I was stuck and found this little unit online from arczone, I paid about 1100 canadian for it shipped in. It's from a mig welder and I think if you new a bit more about electronics then myself you could make it work yourself.
The hardest thing oddly enough was coming up with a good simple one way purge valve, I tried using flow meters thinking that I could measure the argon/air flow coming out of the chamber. I found that the metal ball in the flow meter actually took to much pressure to release and it would push the extra set of gloves right out and you could really feel it on your gloves. Without the one way valve every time you pull your hands out a little you draw air back into the box and contaminate it.
Jim